Energy level analysis of Pm3+:LaCl3

A diagonalization of the matrices representing the combined atomic and crystal-field interactions for the 4f4 configuration has provided the basis for interpreting the spectrum of Pm3+:LaCl3. Experimental data were drawn from the literature and were augmented by unpublished absorption and fluorescence results. A method of truncating the large matrices involved is discussed and shown to yield results in excellent agreement with complete calculations. Use of fluorescence branching ratio calculations based on the Judd–Ofelt intensity theory to monitor the interpretation of fluorescence spectra is discussed.